Watercress Cappuccino with Caviar

Serves 4
Serve with vodka, top quality Sauvignon Blanc or Riesling.

You can serve this frothy, delicately flavored soup in large, heated coffee cups to extend the cappuccino theme, that has become fashionable in many restaurants. This soup is light and has very few calories.

1. In a medium-sized saucepan gently fry the leek in the oil until soft but not colored. Add the potato and stir well. Pour over the vegetable stock and bring to the boil, then cover the pan and simmer for 15 minutes, or until the potato is tender. Add the watercress leaves and immediately remove the pan from the heat.

2. Spoon the mixture into a blender or food processor and process to a purée. Return to the pan and add the plain yogurt and seasoning. Reheat the soup gently over a low heat. For the frothy finish, use a hand-held blender and whiz the soup until foamy. Serve warm with a spoonful of caviar on top.